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The derivation and understanding of Partial Differential Equations relies heavily on the fundamental knowledge of the first years of scientific education, i.e., higher mathematics, physics, materials science, applied mechanics, design, and programming skills. Thus, it is a challenging topic for prospective engineers and scientists.
This volume provides a compact overview on the classical Partial Differential Equations of structural members in mechanics. It offers a formal way to uniformly describe these equations. All derivations follow a common approach: the three fundamental equations of continuum mechanics, i.e., the kinematics equation, the constitutive equation, and the equilibrium equation, are combined to construct the partial differential equations.
This book is the second edition of an introduction to modern computational mechanics based on the finite element method. It includes more details on the theory, more exercises, and more consistent notation; in addition, all pictures have been revised. Featuring more than 100 pages of new material, the new edition will help students succeed in mechanics courses by showing them how to apply the fundamental knowledge they gained in the first years of their engineering education to more advanced topics.
In order to deepen readers’ understanding of the equations and theories discussed, each chapter also includes supplementary problems. These problems start with fundamental knowledge questions on the theory presented in the respective chapter, followed by calculation problems. In total, over 80 such calculation problems are provided, along with brief solutions for each.
This book is especially designed to meet the needs of Australian students, reviewing the mathematics covered in their first two years at university. The 13-week course comprises three hours of lectures and two hours of tutorials per week.
This study aid on numerical optimization techniques is intended for university undergraduate and postgraduate mechanical engineering students. Optimization procedures are becoming more and more important for lightweight design, where weight reduction can, for example in the case of automotive or aerospace industry, lead to lower fuel consumption and a corresponding reduction in operational costs as well as beneficial effects on the environment. Based on the free computer algebra system Maxima, the authors present procedures for numerically solving problems in engineering mathematics as well as applications taken from traditional courses on the strength of materials. The mechanical theories focus on the typical one-dimensional structural elements, i.e., springs, bars, and Euler–Bernoulli beams, in order to reduce the complexity of the numerical framework and limit the resulting design to a low number of variables. The use of a computer algebra system and the incorporated functions, e.g., for derivatives or equation solving, allows a greater focus on the methodology of the optimization methods and not on standard procedures.
The book also provides numerous examples, including some that can be solved using a graphical approach to help readers gain a better understanding of the computer implementation.
This book offers an update on recent developments in modern engineering design. Different engineering disciplines, such as mechanical, materials, computer and process engineering, provide the foundation for the design and development of improved structures, materials and processes. The modern design cycle is characterized by the interaction between various disciplines and a strong shift to computer-based approaches where only a few experiments are conducted for verification purposes. A major driver for this development is the increased demand for cost reduction, which is also linked to environmental demands. In the transportation industry (e.g. automotive or aerospace), the demand for higher fuel efficiency is related to reduced operational costs and less environmental damage. One way to fulfil such requirements is lighter structures and/or improved processes for energy conversion. Another emerging area is the interaction of classical engineering with the health and medical sector.
Stoff- und Formleichtbau
(2020)
Dieses Lehrbuch stellt die unterschiedlichen Leichtbaukonzepte anhand einfacher eindimensionaler Strukturen in sehr verständlicher Weise dar und ermöglicht einen leichten Einstieg in das Thema. Es werden nachvollziehbare Informationen und Hinweise zur Werkstoffauswahl und geometrischen Gestaltung von Bauteilen gegeben.
Viele Studierende erleben das Lernen auf Klausuren als anstrengend, ermüdend und wenig motivierend. Oftmals liegt das nicht am mangelnden Interesse an dem Thema, sondern entsteht dadurch, dass das Lernen allein und ohne direkte Rückmeldung zum Lernerfolg erfolgt.
Um hier eine neue, motivierendere Möglichkeit des Lernens zu schaffen, wurde von Studierenden der technischen Betriebswirtschaft an der Hochschule Esslingen ein haptisches Planspiel entwickelt - zum Einsatz in der Lehre und insbesondere zur Klausurvorbereitung in Veranstaltungen zum Qualitätsmanagement in Bachelorstudiengängen. Die Spieler müssen dabei im Rahmen vorgegebener Zielkorridore und Budgets qualitätsrelevante Entscheidungen treffen, aber auch mit anderen Unternehmen, die im Wettbewerb zum eigenen Unternehmen stehen, punktuell zusammenarbeiten und auf exogene Einflüsse reagieren. Die gelernte Theorie findet sofort eine praktische Anwendung und durch Diskussion mit den anderen Mitspielern ergibt sich ein unmittelbares Feedback zu den eigenen Antworten im Sinne eines Peer Learnings.
Industrie 4.0 und Big Data
(2020)
This document defines three YANG 1.1 [RFC7950] modules to support the configuration of TCP clients and TCP servers, either as standalone or in conjunction with a stack protocol layer specific configuration.
Power-to-Heat
(2020)
This paper provides an analysis of the trend in autonomous driving traffic and the development of infrastructural support, whereas the requirements on the infrastructural support will be analyzed. Then selected traffic scenes will be implemented in an autonomous driving simulator tool in order to figure out the required parameters to assist the autonomous vehicle from the infrastructure.
Metal additive manufacturing of dental prostheses consisting of cobalt−chromium−tungsten (Co−Cr−W) alloys poses an alternative to investment casting. However, metal additive manufacturing processes like Laser Powder‐Bed Fusion (LPBF) can impact the elastic constants and the mechanical anisotropy of the resulting material. To investigate the phase compositions of mechanically different specimens in dependence of their postprocessing steps (e. g. heat treatment to relieve stress), the current study uses X‐ray Diffraction (XRD), Electron BackScatter Diffraction (EBSD), and Transmission Electron Microscopy (TEM) for phase identification. Our studies connect plastic deformation of Remanium star CL alloy with the formation of the hexagonal ϵ‐phase and heat treatment with the formation of the D024‐phase, while partially explaining previously observed differences in Young's moduli.
This paper aims to analyze the stress and strain states appearing in the elbow of a tube, such as those commonly used in a city’s water supply network. The stress field is characterized by the fact that there is a significant stress increase when compared to a straight tube. As a result, the strength of such an elbow must be investigated and guaranteed for such a network to be well designed. A practical solution used is to anchor the elbow in a massive concrete block. The paper compares the stress field that occurs in the elbow when it is free, buried in the ground, and when it is anchored in a massive concrete block. Furthermore, we investigate how a crack appears and propagates in the elbow. This happens especially for the elbow buried in the ground where the stress and strain are higher than when the elbow is anchored in concrete. The results obtained can be used in the current practice in the case of water supply networks made by high-density polyethylene pipes.
Partner oder Konkurrenten? Die Automotive-Branche auf der Suche nach neuen Kooperationsstrategien
(2020)
Durch die Reduzierung der Wertschöpfungstiefe in vielen Unternehmen nehmen die Herausforderungen an das Qualitätsmanagement stetig zu. Der Zuwachs an nationalen, aber auch internationalen Lieferanten lässt die Anzahl der Auditierungen zur Qualifizierung und Entwicklung von Lieferanten stetig steigen. In diesem Zusammenhang müssen neue Lösungsansätze entwickelt werden, um die notwendigen Ressourcen optimal zu nutzen und die entstehenden Kosten möglichst gering zu halten.
Das Interesse der Industrie an additiv gefertigten Bauteilen steigt z unehmend, wobei mit zunehmendem Verständnis der statischen Kennwerte nunmehr der Fokus in Richtung der dynamischen Festigkeiten wandert. Deswegen werden Einflussparameter auf die Lebensdauer und potenzielle Nachbearbeitungsmethoden untersucht und analysiert. Ein großer Einfluss ist dabei der Oberflächengüte und den durch Rautiefen initiierten Kerbeffekten zuzuschreiben. Deswegen werden unterschiedliche Methoden zur Verbesserung der Oberflächengüte untersucht. Dabei werden die Verfahren Laserpolieren, elektrochemisches Polieren und Hartmetallkugelstrahlen und deren Auswirkung auf Oberflächengüte sowie Härte untersucht. Für das elektrochemische Polieren werden die Proben in einer Perchlorsäure für 90 s bei 32 V und maximal 10 A poliert. Das Hartmetallkugelstrahlen wird mit einem UFS 100 Strahlmittel bei einem Druck von 4 bar und einer Strahldauer von 10 s ausgeführt. Anschließend werden Wöhlerlinien für die unterschiedlichen Zustände mittels Umlaufbiegeversuch ermittelt, welche mit Referenzwerten analysierter konventioneller Proben verglichen werden. Des Weiteren werden die Bruchflächen analysiert. Die Untersuchungen ergaben ein hohes Optimierungspotenzial der additiv gefertigten Proben bei einer Verdichtung der Oberfläche sowie einer Entfernung der Randschicht durch eine spanende Bearbeitung. Dadurch wurden höhere Zeitfestigkeiten als mit konventionell gefertigten Proben erreicht.
Electrochemical strain microscopy (ESM) is a powerful atomic force microscopy (AFM) mode for the investigation of ion dynamics and activities in energy storage materials. Here we compare the changes in commercial LiFePO4 cathodes due to ageing and its influence on the measured ESM signal. Additionally, the ESM signal dynamics are analysed to generate characteristic time constants of the diffusion process, induced by a dc-voltage pulse, which changes the ionic concentration in the material volume under the AFM tip. The ageing of the cathode is found to be governed by a decrease of the electrochemical activity and the loss of available lithium for cycling, which can be stored in the cathode.
This paper uses several techniques to monitor the ageing of commercial LiFePO4 cells, which are cycled at 55 °C and −20 °C at various depths of discharge. Ageing at lower depth of discharge leads to higher capacity fading, as compared to higher depth of discharge. The highest capacity fading is observed using 50% depth of discharge for cycling at 55 °C, while the lowest capacity fading is observed for the cells aged at 100% depth of discharge when cycled at −20 °C. Using incremental capacity analysis and differential voltage analysis the capacity fading is monitored and underlying ageing mechanisms are described. The loss of lithium inventory and the loss of active material, especially on the cathode side, are the major degradation mechanisms for the cells. The first incremental capacity analysis peak of the discharge process can be used in our case to predict remaining life and cell capacity.
The paper presents post-mortem analysis of commercial LiFePO4 battery cells, which are aged at 55 °C and − 20 °C using dynamic current profiles and different depth of discharges (DOD). Post-mortem analysis focuses on the structure of the electrodes using atomic force microscopy (AFM) and scanning electron microscopy (SEM) and the chemical composition changes using energy dispersive X-ray spectroscopy (SEM-EDX) and X-ray photoelectron spectroscopy (XPS). The results show that ageing at lower DOD results in higher capacity fading compared to higher DOD cycling. The anode surface aged at 55 °C forms a dense cover on the graphite flakes, while at the anode surface aged at − 20 °C lithium plating and LiF crystals are observed. As expected, Fe dissolution from the cathode and deposition on the anode are observed for the ageing performed at 55 °C, while Fe dissolution and deposition are not observed at − 20 °C. Using atomic force microscopy (AFM), the surface conductivity is examined, which shows only minor degradation for the cathodes aged at − 20 °C. The cathodes aged at 55 °C exhibit micrometer size agglomerates of nanometer particles on the cathode surface. The results indicate that cycling at higher SOC ranges is more detrimental and low temperature cycling mainly affects the anode by the formation of plated Li.
Additive manufacturing offers unique possibilities to produce complex components, which would not be possible or only very difficult to be realizable with conventional manufacturing processes. The potential of additive manufacturing of aluminum alloys has already been realized in prototyping, but still offers potential in the establishment of series applications. For enabling the establishment of additive manufacturing in series applications, comprehensive knowledge about the material behavior is necessary. This study examines the torsional behavior of additive manufactured AlSi10Mg samples and shows the correlation between tensile and torsional strength. Comprehensive torsion tests with strain gauges were performed and significant directional dependencies were shown. The correlation factor in the area of torsional yield strength/tensile yield strength and torsional strength/tensile strength was determined and was compared with the yield/failure conditions according to Tresca and von Mises.
Laser powder-bed fusion has become one of the most important techniques in additive manufacturing. For guaranteeing the possibility of manufacturing highly specialized and advanced components, currently intensive research is carried out in this field. One area of this research is the material-specific macroscopic anisotropy, which is investigated in our work by comprehensive static mechanical experiments. The material which was tested within this study was the precipitation-hardenable AlSi10Mg alloy, with the focus on installation space orientation. Tensile and compression tests were performed, the results for the Young's modulus in compressive loading exceeded the previously known values of this material in tensile loading and achieved values of up to 79.8 GPa. As a result of this investigation, a chemical spectroscopic analysis was undertaken and from the actual chemical composition, a relative density of 99.86% of the samples was determined.